You cannot and should not leave chili out overnight.
Leaving chili out overnight can cause the chili to grow bacteria and spoil unless the chili is still being heated in a slow cooker or crock pot.
If the chili was just left out sitting at room temperature overnight or longer than 2 hours or so it should be thrown out as it could contain bacteria and give you food poisoning.
Food that is left out for 4 hours is not safe to eat.
Food should not be left out longer than 2 hours or it can grow bacteria.
However if the food is not perishable then it can be left out longer than 2 hours but food that is perishable or foods that contain, meats, dairy, cheese etc can spoil if left out longer than a few hours.
Foods such as bread, crackers, etc can be left out longer but foods that contain meat, dairy or are perishable must be kept refrigerated if not eating or consuming them within 2 hours or they can spoil.
Cooked food sitting at room temperature is in what the USDA calls the “Danger Zone,” which is between 40°F and 140°F.
In this range of temperatures, bacteria grows rapidly and the food can become unsafe to eat, so it should only be left out no more than two hours.
According to the USDA Food that has been left out of the fridge for more than two hours should be thrown away.
At room temperature, bacteria grows incredibly fast and can make you sick.
Reheating something that has been sitting at room temperature for longer than two hours won't be safe from bacteria.
The 2 Hour/ 4 Hour Rule tells you how long freshly potentially hazardous foods*, foods like cooked meat and foods containing meat, dairy products, prepared fruits and vegetables, cooked rice and pasta, and cooked or processed foods containing eggs, can be safely held at temperatures in the danger zone.
Food starts to spoil when the temperature rises above 40 degrees.
After food warms to that temperature, you have just two hours in which you can either return it to cold conditions or cook it. In the fridge, produce will survive most power failures, but dairy products should be discarded if they smell or taste sour.
If a perishable food (such as meat or poultry) has been left out at room temperature overnight (more than two hours) it may not be safe.
Discard it, even though it may look and smell good. Never taste a food to see if it is spoiled.
Use a food thermometer to verify temperatures.